As a Canadian, I know how frustrating some online shops can be with international shipping. It's super frustrating when you find an item you want, but they refuse to ship to you or they make a terrible effort to find a reasonable shipping method.
A recent example is Cubic Tech. I wanted to order cuben from them and they said the only shipping option was $123.25 to Canada. I ended up paying them $15 to ship to a USA address and then paying another $15 or so to get the cuben shipped up to me. A lot of time and money would have been saved if they would have just tossed it in a USPS flat rate box for $10 or so.
A popular thing right now seems to be 'free shipping' sales on online gear websites and/or websites that always have free shipping to the USA. These sales are fine, but sellers should consider allowing international customers to get a credit similar to the discount USA customers get. So if a company ships for $8/order on average, they should give international customers an $8 discount on their shipping. It just doesn't make sense to have sales that only apply to a portion of your customer base and it's frustrating.
Regarding the shipping methods, basically all couriers (UPS, DHL, FedEx etc) charge outrageous fees on top of the applicable tax. All sellers need to do is use the regular postal system and declare the value accurately and pretty much everyone will be happy. It boggles my mind why some sellers randomly list the value way higher than it is. The listed value should be the price paid, not the MSRP or some inflated number in case there is an insurance claim. eBay sellers are the worst for listing the retail price rather than the price paid. When I bought a MSR Carbon Reflex 2 on eBay last summer for ~$350 I contacted the seller to make sure he declared the shipping value accurately and he assured me that he would. A few weeks later the tent showed up listed at $600...very frustrating stuff and it tied up a lot of money for about 2 months until I got a refund from the government.
BTW, Canadian customers should be aware that there is an obscure tariff on tents that charges 30% tax on top of the 12% HST. I've bought several tents online and only had this charged once, but it can happen. With the MSR CR2 I would have been better off to just buy it at a local gear shop rather than pay an extra 30% tax.